The present invention relates to a sealing device for a gear box and includes a cap mounted to the shaft, and the cap includes a receiving space in which a seal is engaged. The seal prevents oil flowing into the gap between the bearing frame and the bearing.
A conventional gear box is shown in FIG. 4 and generally includes a worm rod 20 rotatably received in the box 10. One end of the worm rod 20 is rotatably connected to an inside of the gear box 10, and the other end of the worm rod 20 extends from an opening 11 of the gear box 10. A bearing 60 is engaged with the opening 11 of the gear box 10, and second end of the worm rod 20 is supported by the bearing 60 and connected with a driving shaft. A seal 61 is mounted to the second end of the worm rod 20 and prevents oil in the gear box 10 from leakage. In order to have a better result of sealing, the seal 61 has to be securely mounted to the worm rod 20 while allowing the worm rod 20 to rotate as desired. The friction between the seal 61 and the second end of the worm rod 20 is too large and consumes the energy for driving the worm rod 20. The seal 61 is replaced frequently because of wearing. FIG. 5 shows an improved sealing device which includes a plate 80 mounted to the rotatable shaft 72 in the gear box 70. The plate 80 has a flange 81 which is mounted to a flange 71 extending from an inside of the box 70. A bearing 90 is engaged with a hole defined through the wall of the box 70 and is covered by the plate 80. A seal 91 is mounted to an end of the shaft 72 which extends from the hole of the box 70. The plate 80 separates the oil in the box 70 to prevent the oil from entering the gaps between an inner periphery of the hole and the beating 90 when the rotatable shaft 72 is rotated. The arrangement of the plate 80 does not require the seal 91 to be secured to the rotatable shaft 72, so that the friction between the rotatable shaft 72 and the seal 91 is less than that in the example shown in FIG. 4. Sealing by the plate 80 is not satisfied when the rotatable shaft 72 is not rotated, because the oil may flow over the flange 81 of the plate 80 and then enter into the bearing 90 and the gap between the bearing 90 and the inner periphery of the hole of the box 70.
The present invention intends to provide a sealing device for a gear box wherein a seal is received in a space of a cap so as to prevent the oil flowing into the gap between the bearing and the frame even when the worm rod is not rotated.
In accordance with one aspect of the present invention, there is provided a sealing device for a gear box, and the device comprises a box having a hole defined through a wall thereof. A shaft has a first end rotatably engaged with an inside of the box, and a second end of the shaft extends through the hole. A frame is engaged with the hole of the box, and a bearing is engaged in the frame. The bearing is mounted to the second end of the shaft. A cap is connected to an end of the frame in the box, and a seal is located inside of the cap. The seal has a flexible plate which is engaged with the end of the frame in the box.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.